Frank armstrong



(No Model.) v

P. STRONG.

THE. UTTING DIE.

No. 269,153. Patentgd, De0.12, 1882.

, UNITED STATES PATENT OFFICE.

FRANK ARMSTRONG, OF BRIDGEPORT, ooNNEoriour.

THREAD-CUTTING DIE.

' f SPECIFICATION forming part of Letters Patent No. 269,153, datedDecember 12, 1882,

Application filed September 7, 1881. (No model.)

I0 all whom it may concern Be it known that I, FRANK ARMSTRONG, acitizen of the United States, residing at Bridgeport, in the county ofFairfield and State of Connecticut, have invented new and usefulImprovements in Thread-Cutting Dies, of which the following is aspecification.

My invention relates to certain new and useful improvements in dies forcutting screwthreads upon pipes and bolts.

Prior to my invention screw cutting dies have been made in twof0rmsviz., the solid or non-adjustable die and the adjustable orvariable die. The latter, while they may be adjusted to out threads uponpipes of different diameters, have the disadvantage in ordinary use offrequently being accidentally or ignorantly altered in their adjustment,resulting in great annoyance, and hence for many purposes the solid ornon-adjustable dies are preferred; but in this class anotherdisadvantage follows-viz., it becomes necessary to have a special dieforevery size pipe or bolt upon which athread is to be out, and, as thedies should be made of fine steel, it is obvious that a large amount ofmetal is necessary to produce any considerable number ofsizes, and

this involves not only great expense in the cost of material, but alsoin skilled labor to produce the dies.

My invention has for its object tosecure the advantages incident to bothclasses of dies, while avoiding all the objections named; and with theseobjects in view my invention consists in making a series of die framesor helders of base metal-such as malleable cast-' be removed from oneblock and located in another of different size, whereby with one set ofcutters and any number of frames or holders, cutting-dies may beproduced adapted to cut pipes or bolts of any desired diameter, as willbe hereinafter and in detail explained.

In order that others may fully understand my invention, 1 will proceedto describe the construction and operation of the same, referring byletters to the accompanying drawings, in which-- 4 Figure 1 is a planview of two of my improved frames or holders, having central openings ofdifferent sizes, and adapted to pass over pipes or rods of two differentdiameters. 1 have shown one of these holders fitted with four threadedcutters, and the other with three, one being removed to expose the seatupon which the cutter rests when in place. Fig. 2 is a vertical sectionof one of the holders, taken at the line or .rof Fig. 1, and Fig. 3 .isabottom perspective view of one of the cutters removed.

. Similar letters denote like parts in all the figures of the drawings.

- A A are cast malleable-iron frames or holders with central opening, B,adapted to receive a pipe or bolt upon which a thread is to be cut.Surrounding the pipe-opening B are arranged two or more openings orvertical channels, 0, which are formed with special reference to thereception of independent thread cutters or tools D. The grooves orchannels 0 have near the bottom thereof an inwardlyprojecting flange orseat, a, upon which rests the bottom of the cutter or tool-'D when inits proper porespective channels or seats are numbered, and are soaccurately formed and proportioned that cutter No. 1, taken from oneblock or frame, will fit in seat No. 1 of any other block orframe.Forinstance, suppose that the block or frame A, being designed for usein cutting threads upon inch-pipe, is equipped with four cutters, allproperly held in place by bindingsition, where it is held againstaccidental disthe block or frame A. The cutters and their 7 sirable tocut a thread upon a two-inch pipe. To accomplish this, itis onlynecessary toloosen the binding-screws E, remove cutters 1 2 3 4 from theblock or frame, and to transfer them to seats 1 2 3 4 in another blockor frame intended for two-inch pipe. The cutters are secured therein bythe binding-screws, and the instrument is now ready for use either in astock, lathe, or other pipe-thread-eutting machine. It will be observedthat the cutters bear a positive and fixed relation',to the center oraxis of each block or frame within which they may be located, and hencethe frames maybe readily centered to perform their work. The lower endsof the cutters are formed, as shown at Fig. 3, so that they will seatthemstlves. upon the flange a in the block or frame, while the top-andbottom of the cutter lie flush with the sides of the said frame.

While I have shown the cutters with cylindrical backs and convergingsides, I do not wish to confine myself to this particular shape, as anyother may be adopted, provided it be such as to prevent any movement ofthe cutterswhen seated in the blocks or frames.

It will also beuuderstood that cutters adapted to cut threads ofdifferent pitches may be substituted for each other in my improvedframes or holders, and from the construction and arrangement of theparts that a series of cheap, durable, and positively accuratethreadcutting dies are produced.

What I claim as new, and desire to secure by Letters Patent, is-

1. The block or frame A for screw-cutting dies, having a central openingfor the passage of the pipe or bolt to be cut and vertical channels atpoints surrounding such central pipepassage and forming seats therein ofthe ex-' act size and contour of the holding parts or shanksofthecutting-dies,ineombination with the removable dies to be seatedtherein and means for fastening them firmly in position,substan'tiallyas and for the purpose described.

2. A series ofplates constructed as described, and adapted. to cuttingpipes or bolts of. different sizes, in combination with a set of diesadapted to be used interchangeably with said die-plates, substantiallyas set forth and described.

In testimony whereof have hereunto set my hand in the presence of twosubscribing witnesses.

FRANK ARMSTRONG.

Witnesses:

T. R. GRUTTENDEN, F. T. STAPLES.

